1. Field of the Invention
The present invention relates to a joint method for a reinforcing bar using a grout-filled reinforcement joint constituted of a strong elongated tubular body.
2. Related Background Art
A grout-filled reinforcement joint (hereinafter referred to as a reinforcement joint) is buried in reinforced concrete and is used for joining various reinforcing bars such as deformed reinforcing bars (hereinafter referred to as reinforcing bars) including round steel reinforcing bars or screw node reinforcing bars in the reinforced concrete.
A reinforcement joint is disclosed in Japanese Patent Application Publication No. 5-61422 and so on. The reinforcement joint is constituted of a strong elongated cylindrical body opened at both ends. Reinforcing bars as a pair are inserted into the cylindrical body from opposite directions, and then a grout (which is a filling material including mortar, epoxy resin, and so on and has high strength) is injected and filled. The reinforcing bars are fixed in the cylindrical body by hardening of the grout, and thus the reinforcing bars as a pair are joined.
When the reinforcement joint is employed, an end of a reinforcing bar is not required to be processed, and a precision cut is not required. In addition, eccentricity and inclination of the reinforcing bar at the joining portion are within a tolerable range, and the reinforcement joint has such an excellent feature that residual elongation and shrinkage do not occur at the joining portion.
In the above reinforcement joint, in the injection of a grout into a conventional reinforcement joint, there has been employed a process of fitting a tubular body such as a vinyl tube into the inlet, connecting a cylinder head of a discharge pipe of a pump for injection, and injecting and filling the grout. In this process, after the injection, the tubular body or the cylinder head of the discharge pipe is removed from the inlet, and a rubber stopper is required to be fitted into the inlet. Thus, there is a problem that a large amount of the grout once filled leaks outside while the tubular body or the cylinder head of the discharge pipe is removed from the inlet.
In order to prevent the leakage of the grout, after the injection is terminated, a front end of the cylinder head of the discharge pipe of the pump for injection is folded and then tied with a wire, and the grout starts to be hardened. The grout is left as it is until the flowability of the grout is lost, and then the operation of removing the tubular body is required to be performed. However, since several hours or half a day is required before the next operation, in order to increase efficiency, the operation of a pump for injection is not interrupted, the front end of the cylinder head of the discharge pipe is cut and bent for each single injection to stop the leakage of the grout, and the injection operation in the next portion is advanced. However, in this method, the injection operation is complicated, and there is a problem that cost is increased.
An opening of a communicating tube or a continuous hole is previously fitted with a rubber stopper on the grout outlet side of the reinforcement joint to prevent the leakage of the grout being filled, and when the flowability of the grout is lost after the filling of the grout, the operation of removing the rubber stopper is performed. The grout initially flowing from the opening is a muddy liquid rich in paste components, and this is because the grout being injected is slightly separated, and light paste components are easily assembled to the injection front end. Excess water is discharged due to the leakage of the muddy liquid, so that the grout becomes a strong filling material, and therefore, the injection is required to be continued until the muddy liquid is discharged outside.
However, since the opening of the communicating tube or the continuous hole is on the same plane as an outer wall surface of the reinforcement joint, the muddy liquid drips down along the outer wall surface, and there is such a drawback that the muddy liquid contaminates the outer wall surface. Thus, although a cleaning operation referred to as deburring is required to be performed after the injection, this operation requires time and expense, and this is a source of concern to workers. After a hardened material of the muddy liquid deposited onto the outer wall surface is removed by deburring, there is a problem that a discolored area infiltrated with the muddy liquid remains and deteriorates the appearance of the outer wall surface. Furthermore, in the case of at-once injection, it takes time to confirm whether the grout is simultaneously filled in a large number of reinforcement joints.